Power line cables are a pervasive medium that reaches nearly all homes and businesses and provides a very useful technique for delivering digital services to customers as well as providing local area networking (LAN) capabilities. However, power line cables are not able to provide links dedicated exclusively to a particular subscriber, as can twisted pair cables, because they are a shared medium. More specifically, power line cables that extend from a low voltage transformer to a set of individual homes or to a set of multiple dwelling units are shared among a set of users. This means that the signals that are generated by one user in one apartment or house may interfere with the signals generated in an adjacent apartment or house. Because it is impossible to locally contain the signals generated by a user, the more users in geographical proximity that use power line communications (PLCs), the more interference will be generated. As the interference increases, every user will experience a decrease of data rate as more packet collisions will occur.
This phenomenon can also occur in a single network. In fact, as the number of nodes in the network increases, the probability of packet collision grows, and the overall throughput of the single network decreases. Therefore, it would be desirable to provide to PLC devices a technique to maintain optimized performances, even in the presence of many nodes or multiple networks, with the ultimate goal of increasing overall network throughput.